Now this year Apple seems to be looking to improve on their location based services by acquiring WifiSlam, an indoor GPS location service for $20 million. WifiSlam was founded back in 2010 by Joseph Huang and Jessica Tsoong. WifiSlam makes use of mobile apps to determine the exact location of a person inside a building via wi-fi signals
WifiSlam uses simultaneous location and mapping(SLAM) technique where the device bots build maps of the surrounding and keep track of the device’s location in the map. You can watch Huang talk about SLAM in the following YouTube video: